This invention relates to insulated roof support structure, and more particularly to an insulated support bar for the bottom of each purlin.
In the fabrication of a metal building including a metal sheet roof supported upon elongated parallel purlins mounted on transverse rafters, the roof has been insulated by various methods of installing loose insulation or layers of insulation material within the spaces between the purlins and below the sheet metal roof. Most of the methods for supporting the insulation material within each purlin cavity, that is the space between adjacent purlins, has been rather complex and expensive. Moreover, the labor for installing such insulation systems has also been expensive.
Various types of roof insulation support systems are disclosed in the following U.S. patents:
______________________________________ 3,969,863 Alderman Jul. 20, 1976 4,047,345 Alderman Sep. 13, 1977 4,047,346 Alderman Sep. 13, 1977 4,075,806 Alderman Feb. 28, 1978 4,075,807 Alderman Feb. 28, 1978 4,147,003 Alderman Apr. 3, 1979 4,172,345 Alderman Oct. 30, 1979 4,375,742 Paliwoda Mar. 8, 1983 4,384,437 Coles May 24, 1983 4,434,601 Zellmer Mar. 6, 1984 4,566,239 Smigel et al Jan. 28, 1986 4,573,298 Harkins Mar. 4, 1986 ______________________________________
All of the above Alderman patents and the Harkins U.S. Pat. No. 4,573,298 disclose insulated roof structures incorporating a lattice-work of longitudinal and/or cross straps or transverse straps for supporting insulating material.
Alderman U.S. Pat. Nos. 3,969,863, Alderman 4,047,345, Alderman 4,047,346, Alderman 4,075,806, Alderman 4,147,003 (Insulating strip 14), Zellmer, Smigel, and Harkins (Col. 7, lines 23-26) disclose elongated insulated strips secured upon the top flange of each purlin.
Alderman U.S. Pat. Nos. 4,147,003 (FIGS. 3 and 4), Paliwoda (FIG. 3A), Coles, and Harkins (Col. 7, lines 23-26) disclose the use of elongated insulated strips fitted longitudinally upon the bottom surface of the bottom flange of each purlin.
However, none of the above patents disclose a roof insulation system in which an elongated insulated support bar is secured against the bottom flange of a purlin, trapping the cross straps between the support bar and the purlin, in order to completely insulate the purlin by means of a single fastener member for each transverse support strap and purlin.